The Connection Between Hearing Loss and Healthy Aging
The physical, cognitive, psychological, and psychosocial consequences of hearing loss were a prominent topic at the workshop. This chapter brings together six presentations that focused on these issues. Together, they demonstrate that hearing loss is not only a pervasive problem but also one that can affect virtually all aspects of a person’s life.
THE CONSEQUENCES OF UNTREATED HEARING LOSS
James Firman National Council on Aging
Jim Firman has had a hearing loss his whole life.1 “I understand, at a personal level, the benefits and limitations of treatment,” he said. In addition, as president and chief executive officer of the National Council on Aging, an organization whose mission is to improve the lives of millions of older adults, he is alarmed by both the prevalence and the consequences of untreated hearing loss.
First, he observed, hearing loss is very common. Firman said that 2 of every 100 children have hearing loss, as does 1 of 14 people under age 65. Of people between the ages of 65 and 84, he said 40 percent have hearing losses, as do 2 of 3 people over the age of 85.
1 Firman demonstrates what his hearing sounds like in the video of his presentation, which is available at http://www.iom.edu/Activities/PublicHealth/HearingLossAging/2014-JAN-13.aspx (accessed February 24, 2014).
Hearing loss is also invisible. No one can tell that people have a hearing loss or the severity of the loss by looking at them. “You have really no idea what it means to them,” Firman said. In addition, hearing loss is invisible to many who have hearing loss. They are aware that they are missing things, but they do not have a clear idea of how much or what they have missed. They do not know how much they do not hear of what their bosses, their coworkers, their spouses, their children, or their grandchildren are saying. “Most people with hearing loss do not understand what they are missing, and, therefore, they are not motivated to take action.”
Hearing loss is also insidious. The consequences are not obvious, but they can have psychophysical, cognitive, and psychosocial impacts. Most important, said Firman, the inability to communicate well makes it much harder to remain an active, engaged, and contributing member of society. For example, he recounted an episode where he was unable to hear his adult son ask whether he wanted to go out for dinner. “It is the insidious, subtle consequences in everyday situations where we need to focus the most attention.”
Finally, hearing loss is treatable, he said. Even people with severe hearing loss can function at a much higher level with proper hearing aids and treatment. Firman himself relies not only on good hearing aids but also on good speech-reading skills. If he closes his eyes, he can miss half of what a person is saying. “If we want to correct this problem among older adults, it is not just about amplification. It is about auditory training and speech reading as well.”
Barriers to Treatment
Yet hearing loss often remains untreated. Nine of ten people with mild loss do not have hearing aids, Firman observed. Six of 10 people with moderate to severe hearing loss do not have hearing aids, and 70 percent of people between age 65 and 84 do not use hearing aids. Firman described a study conducted by the National Council on Aging in 1999 on the consequences of hearing loss in older adults—he noted that 69 percent of the people with untreated hearing loss said that their hearing was not bad enough to require a hearing aid. “I can guarantee you, as a person with a moderate to severe loss, that there is no way that you are doing fine and getting along fine if that hearing loss is not treated.”
One of five people in the survey also said that wearing a hearing aid would make them feel old or embarrassed. Yet they are not too embarrassed to respond inappropriately, to withdraw from situations, or to be viewed as senile, said Firman. “This is just astounding to me.”
Hearing loss is not a priority for policy makers, Firman observed. They are not seriously talking about expanding coverage for hearing aids. Policy makers and the general public are unsure about whether hearing loss is a
lifestyle issue, a health care cost issue, or a public health concern. Medicaid, which has provided some coverage for hearing aids in the past, may be cutting back because of cost pressures, despite the cost-effectiveness of hearing aids. Only the U.S. Department of Veterans Affairs has steadfastly supported their use.
Finally, hearing loss is a solvable public health challenge, he said. Interventions exist and work. “What we have to do is create the awareness of the problem and move together with collective action to make a difference.” This workshop, Firman concluded, could mark a historic turning point for age-related hearing loss.
THE IMPACT OF HEARING LOSS ON PHYSICAL FUNCTIONING
Alan M. Jette Boston University School of Public Health
Hearing loss is seen by many people to be a communication disorder, but it may have much more wide-ranging consequences. It could increase the risk of falls and injuries, lead to increased functional limitation and subsequent disability, and reduce one’s activity and participation, leading to decreased quality of life.
Alan Jette, director of Boston University’s Health and Disability Research Institute, reviewed some recent longitudinal studies on the potential functional consequences of hearing loss. With regard to falls, a study of twins in Finland hypothesized that postural balance would act as an important mediator between hearing loss and falls. In a study of 423 women with a mean age of 68 years, rates of falls for the best to the poorest hearing quartiles were 7.1, 6.7, 10.4, and 11.3 falls per 100 person-months (Viljanen et al., 2009). In the poorest hearing group, 30 percent reported two or more falls versus 17 percent in the best hearing group. Even after controlling for postural balance, those with poor hearing still had a twofold increased risk of falls. The same study looked at the impact of hearing loss on walking ability. Of 434 women ages 63 to 76, 41 percent of those with impaired hearing correlated cross-sectionally with poor mobility. In age-adjusted logistic regression, the women with hearing loss had twice the risk for new major difficulties in walking 2 kilometers as those without hearing loss.
The Health ABC study, which is a population-based study of 3,000 individuals ages 70 years and older, has also looked at the association of age-related hearing loss with function and disability. In a prospective cohort study of more than 2,200 adults ages 70 to 79 (Chen et al., in review), observed a small “dose-dependent” effect of hearing with functional loss, with greater levels of hearing loss associated with poorer function over time and, among women, greater risk for incident disability. Results were robust
to adjustment for multiple potential confounders. Women with moderate or greater hearing loss had a 31 percent greater increased risk of disability compared with those with normal hearing. This association was not seen for men in this cohort study.
Fully adjusted analyses restricted to individuals with mild or greater hearing loss found that individuals who used hearing aids had functional scores that were not significantly different from individuals not using hearing aids. Hearing aid use also brought no significant attenuation in the risk of incident disability. Nevertheless, data on key variables—such as the hours a hearing aid was worn per day, the number of years used, and the adequacy of rehabilitation—that may affect the success of hearing rehabilitation and any observed association were not available in the Health ABC study.
Another study in Alameda County, California looked at the association of hearing loss with the ability to perform activities of daily living (ADLs), instrumental activities of daily living (IADLs), physical performance, depression, and social participation. A 1-year prospective cohort study in a sample of about 2,500 people found no consistent association between hearing loss and performance of ADLs, IADLs, or physical performance (Wallhagen et al., 2001). The study did, however, see a clear association with social functioning, as measured by feeling left out, feeling lonely or remote, finding difficulty in feeling close to others, or not being able to pay attention, with the association higher for those with moderate and severe hearing loss as opposed to mild hearing loss.
Finally, Jette discussed the association between hearing loss and driving behaviors. Research has shown that people with hearing impairments are more likely to have ceased driving (Gilhotra et al., 2001). In a study from Quebec that used a database of driving records, daily noise exposure and measured hearing loss were associated with greater risk of traffic accidents (Picard et al., 2008). And a study from Australia found that people with moderate to severe hearing impairment had significantly poorer driving performance in the presence of auditory distractors (being asked to report sums of numbers) as compared to those with normal or mild hearing impairment (Hickson et al., 2010).
In summary, existing studies on the association of hearing loss with functional decline are inconsistent, Jette said. Some demonstrate a positive association. Others find weak or no significant association. The results depend on such factors as which function is being examined and how hearing loss is measured. Nevertheless, Jette said, on the basis of available literature, hearing loss appears to have some real but relatively modest functional and disability consequences that could affect one’s quality of life. Still, he noted, “the state of the science is far from mature.” For example, the literature has not examined associated factors, such as who can afford an expensive hearing aid and the degree to which hearing aids are worn.
In the future, the exposure variable of greatest interest needs to be clarified, Jette observed. Uncorrected hearing loss is most commonly assessed, which seems appropriate when the focus is on the impact of hearing loss on outcomes such as falls and functional limitations. When the focus is on disability behaviors such as driving and social participation, however, hearing loss with correction may be the more meaningful exposure variable. As other speakers noted, a critical and fascinating question is whether hearing aid use or other forms of correction have a modifying effect on associations with physical functioning. Careful observational studies with and without correction could pave the way for controlled trials. Also, although the functional measures may seem simple, in fact functional outcomes are complex, and work is needed to clarify those most related to hearing loss, Jette said. One’s capacity to perform key functional tasks such as walking and to prevent events such as falls is critical to explore as well.
FUNCTIONAL RESERVES AND HEARING
Luigi Ferrucci National Institute on Aging
As people age, their bodies continually adjust and compensate to maintain good physical and cognitive function, observed Luigi Ferrucci, scientific director of the National Institute on Aging. But when physical and cognitive reserves are depleted and compensation no longer works, declines can follow. Some individuals maintain a high level of functioning up to the last day of their lives. Others start showing functional decline much earlier because of disease or other causes. Extending good function to these latter individuals represents a tremendous public health opportunity.
In addition, hearing loss can have enormous personal consequences. Ferrucci recounted a conversation with a group of centenarians, most of whom had hearing loss, who reported that hearing loss was their number one concern. They were afraid that something was going to happen and that they would not be able to react because they could not hear.
Ferrucci and Studenski (2011) have defined four aging phenotypes that contribute to the genesis of geriatric syndromes:
- Changes in body composition
- Energy imbalance in production or utilization
- Homeostatic dysregulation
In his presentation, Ferrucci focused on energy imbalances, though he said that hearing loss can have effects across all four domains. A healthy
person expends 60 to 70 percent of the energy used each day simply carrying out the body’s basic functions, he said. Someone fighting disease or disability uses even more energy to maintain this homeostatic equilibrium. Instability, infirmity, or inefficiency can further eat into energy stores. As a result, such individuals have less energy for other activities, such as movement or thinking.
The brain has a variety of activities to which it must devote resources, including attention, cognitive function, motor function, balance, hearing, vision, cardiovascular control, and metabolic control. Dual tasks create a competition for brain resources. For example, people talking on their cell phones tend to walk more slowly, and organists know that using the organ’s pedals makes it very difficult to play the keyboard quickly. In young and healthy individuals, additional resources can be pulled from reserves. But in older individuals, functional resources are constrained, which can lead to dysfunction.
When people have trouble hearing, they have to spend more energy to understand what is coming from their ears. Older people also have less functional reserve that they can allocate to this task. As a result, they can have trouble dealing with a separate but simultaneous task, such as walking or dealing with a sudden obstacle. “The entire range of your functional status is going to be affected,” said Ferrucci.
From these observations, Ferrucci drew four conclusions:
- Older age is often associated with a state of brain susceptibility, reduced plasticity, and diminished functional reserve.
- Additional requests to the brain compete with finite resources, which may have functional consequences and increase fragility.
- Because of reduced plasticity, effective adaptation is less likely to occur.
- Hearing loss may have a negative impact on unexpected functional domains.
AGING AND HEARING LOSS: WHY DOES IT MATTER?
Kathleen Pichora-Fuller University of Toronto
When you are hard of hearing you struggle to hear;
When you struggle to hear you get tired;
When you get tired you get frustrated;
When you get frustrated you get bored;
When you get bored you quit.
—I didn’t quit today.
Not everyone is as successful as this acquaintance of Kathleen Pichora-Fuller, professor of psychology at the University of Toronto. Many people respond to this cascade from hearing issues to cognitive issues to emotional issues to social issues by simply withdrawing from social interaction. She noted that this is “absolutely not” what we want to happen to people.
People have many different kinds of hearing loss, Pichora-Fuller said. People can have an audiogram that would not suggest hearing problems, yet they can still have hearing deficits. They may be able to hear someone in ideal listening conditions, where it is quiet, they are listening to just one speaker, the person and topic are familiar, and they are able to focus their attention on the conversation. But in challenging listening conditions—where it is noisy, many people are talking, people have accents or speak quickly, the topic is unfamiliar, or a listener is multitasking or getting used to a new hearing aid—they can have much more difficulty. This can especially be a problem in health care or emergency situations where people need to understand what they are being told.
Older people can particularly have trouble with speech perception in noise, Pichora-Fuller noted. In one test, listeners heard 50 sentences with varying levels of noise and were asked to repeat each sentence’s final word (Pichora-Fuller et al., 1995). Half the sentences had contextual clues about what the final word would be: “Stir your coffee with a spoon.” The other sentences did not provide a helpful context: “John did not talk about the spoon.” Older people with good audiograms needed about 3 dB better signal-to-noise ratio to understand the same number of words. Nonetheless, the older people derived more benefit from the context—again, about a 3 dB difference in the signal-to-noise ratio. Thus, the younger and the older listeners were arriving at about the same performance level but were doing it in different ways. Younger people were more proficient at using the signal, and older people were more proficient at using context.
Age contributes to changes in both hearing and memory, Pichora-Fuller pointed out. In addition, people with lower performance on both memory and hearing measurements tend to attach greater stigma to aging, and hearing problems can result in reduced social participation. The current challenge, she said, is to unpack the connections among these domains using various research approaches and to use new knowledge to inform practice.
Pichora-Fuller stated that hearing loss can have serious widespread health implications in terms of promoting healthy aging. “How do we save people from adverse events that they are likely to encounter because of communication problems?” she asked. “How do we facilitate their ability to self-manage health issues? How do we get them to adhere to and benefit from interventions for health issues that rely on communication?”
Many solutions already exist, and others will be developed through continued research and development. But the solutions need to be com-
bined in a broader perspective that includes the sensory, cognitive, social, and environmental domains, Pichora-Fuller said. For example, hospitals and other health care environments can be extremely noisy. Standards for communication accessibility in such facilities could greatly benefit those with hearing problems.
THE IMPACT OF HEARING LOSS ON COGNITION
Marilyn Albert Johns Hopkins University School of Medicine
Studies are limited but suggestive of the connection between hearing loss and cognition, noted Marilyn Albert, professor of neurology at the Johns Hopkins University School of Medicine. Two longitudinal studies have demonstrated an association between hearing loss and cognitive decline (Lin et al., 2013; Uhlmann et al., 1989), and two others have demonstrated an association with dementia (Gallacher et al., 2012; Lin et al., 2011b). One is part of the Health ABC study. Using a digit-symbol substitution test to measure cognition, in which people write a symbol for each digit on a piece of paper to measure psychomotor speed, executive function, incidental memory, and attention, individuals who had normal hearing performed much better than individuals who had hearing loss (Lin et al., 2013). The data are “striking,” said Albert. “Individuals, even adjusted for level of hearing loss over time, are performing more poorly on this test that doesn’t require that you actually hear.”
The other longitudinal study Albert described is from the Baltimore Longitudinal Study on Aging, a prospective study of older adults that began in 1958. In 639 individuals followed for more than 10 years, those with hearing loss had a higher probability of developing dementia, with the probability rising with the severity of hearing loss (Lin et al., 2011b). In this study, dementia was defined as progressive declines in mental ability to the point of not being able to function independently, with impairments in two or more domains of cognition. The relationship between hearing loss and time to develop dementia is “convincing and striking,” said Albert.
Imaging studies of brain structure have also demonstrated an association with hearing loss. For example, Peelle et al. (2011) showed that poorer hearing is associated with reduced gray matter in the auditory cortices. In addition, Lin et al. (in press), in research on 126 individuals involved in the Baltimore Longitudinal Study on Aging, found a greater loss of mean gray matter volume over time in those with hearing loss versus those who did not lose hearing. Most important, said Albert, the losses occur not just in the brain regions related to hearing but more globally, suggesting that “there is a cascading effect.”
Albert hypothesized that two mechanisms could be at work to explain these associations. First, hearing loss could be causing increased brain atrophy. Second, in people with progressive accumulations of brain pathology due to other causes, such as Alzheimer’s disease or microvascular disease, two pathological processes could be superimposed. These two pathological processes could contribute to declines in cognition and result in crossing a threshold for dementia at an earlier time.
The loss of hearing is obviously modifiable, Albert said. Therefore, a randomized controlled trial in which some individuals were given hearing aids and followed over time along with individuals who did not have hearing aids could demonstrate the effects of hearing loss on cognition and brain volumes, as well as on such factors as social engagement and quality of life, she concluded.
Barbara E. Weinstein Graduate School and University Center, City University of New York
Much more information has recently become available on the psychosocial impacts of hearing loss. Barbara E. Weinstein, professor of audiology and speech language hearing sciences at the City University of New York, provided a brief review of the literature.
Many studies’ samples are available from countries around the world, including the following:
- Blue Mountains Hearing Study: a population-based survey of age-related hearing loss in a representative older Australian community;
- Blue Mountains Eye Study: a population-based study of vision and eye diseases among a representative sample of the older Australian community;
- Survey of Disability, Aging and Careers: a national household survey of 43,233 respondents with and without disability using the Australian Bureau of Statistics;
- Program of Education and Aid for the Community-Dwelling Elderly: a field study of health parameters of community-based older people in Japan;
- National Health and Nutrition Examination Study: a program of studies designed to assess the health and nutritional status of adults and children in the United States;
- Epidemiology of Hearing Loss Study: a population-based longitudinal study of age-related hearing loss of people living in Wisconsin; and
- Medicare Current Beneficiary Statement: a continuous multipurpose survey of a nationally representative sample of older persons with disabilities, and institutionalized beneficiaries.
The functional disabilities reviewed by Jette have major psychosocial impacts, Weinstein noted. For example, Genther et al. (2013) found that people with mild to profound hearing impairments were more likely to have a history of hospitalizations and hospitalization in the past year. Hearing loss was significantly and independently associated with increased health care use, including the number of hospitalizations. And hearing loss was significantly associated with self-reported poor physical and mental health.
Research has also demonstrated a link between hearing loss and social isolation. Weinstein and Ventry (1982) found that people who were socially isolated had a greater self-perceived hearing disability, worse auditory processing difficulties, and poorer hearing. The correlation was stronger with subjective than objective measures of social isolation, and the strongest relationship was with the self-reported hearing disability. In doing this research, Weinstein said that she broke her sample into groups, and the people who were most subjectively and most objectively isolated were the ones with the worst-measured hearing, the greatest self-perceived hearing disability, and the most challenges in auditory processing.
In a more recent study, Hawthorne (2008) found that the likelihood of self-perceived social isolation increased with the number of chronic conditions. Of note, depression had the strongest association with subjective social isolation, followed by self-reported hearing difficulties. Hearing difficulties came up before vision as a correlate of social isolation.
Depression is prevalent in the elderly, with 15 to 20 percent of older adults having been diagnosed with the condition. Like hearing loss, depression is often undetected and untreated. In a study from Canada, MacDonald (2011) found a strong relationship between self-reported hearing problems and depression. Saito et al. (2010), in a study conducted in Japan, found that the odds of depressive symptoms were high in people with self-reported hearing disability as compared to those without hearing disability. Gopinath et al. (2012) also found an independent association between hearing disability and the presence of depressive symptoms after adjusting for age, sex, walking disability, receipt of pension payment, use of community support services, living alone, cognitive impairment, and history of arthritis or stroke.
Hearing loss affects independence by increasing the reliance on support systems, Weinstein stated. Schneider et al. (2010) demonstrated that hearing loss was associated with increased use of community and informal support systems and was a predictor of use of community support after 5 years. In addition, the severity of hearing loss mattered, with people having moder-
ate to severe hearing loss at increased risk for the need to use community support services. People who used support systems were more likely to be hearing aid users, however.
Hearing loss may also be a risk factor for mortality. Karpa et al. (2010) found that hearing loss severity was connected to mortality, but this connection occurred through mediating variables, including walking difficulty and cognitive impairment. This indirect correlation needs to be considered when thinking about the effectiveness of interventions, Weinstein said.
Finally, hearing loss affects quality of life, including a person’s perceptions of health, social interactions, physical function, and psychological function. For example, Dalton et al. (2003) found that self-reported hearing disability and severity of hearing loss was associated with reduced scores on several domains of the SF-36, which is a widely used survey of functional health and well-being. Chia et al. (2007) produced similar results and also showed that the severity and type of hearing loss affect self-reported measures of well-being. Gopinath et al. (2012) also showed that people who developed incident hearing loss were much more likely to have a reduced quality of life.
Weinstein ended on a more positive note. People are more likely to use a hearing aid if they perceive a need for improved hearing, feel disabled by hearing loss, or feel that hearing loss limits their participation in society. Hearing aid users are more likely to score slightly better on the physical summary scores of the SF-36 (Chia et al., 2007), to use and need support services (Schneider et al., 2010), to show significant improvement on the mental domain items of the SF-36 (Gopinath et al., 2012), and to exhibit less decline in the vitality domain than people who do not use hearing aids (Gopinath et al., 2012). Hogan et al. (2009) also found that hearing aid users had a better average quality of life than non-hearing-aid users, though they had a poorer average quality of life than the general population.
Weinstein posed two questions at the end of her talk. What are the absolute and relative risk reductions of hearing interventions, and what is the length of time needed to accrue a clinically meaningful risk reduction in health outcomes associated with hearing difficulties?
Among the most important goals of healthy aging are independence, psychological well-being, successful life course transitions, and self-reported health, Weinstein said. Hearing affects all these measures. “The ability to hear and understand really matters,” she concluded.
During the question-and-answer period, several issues arose which were distinct from the presentations above and so are reflected here.
Weinstein and Albert agreed that there is a great need for randomized controlled trials on the efficacy of hearing aids in improving health outcomes, especially because so much of the data available today remain correlational rather than causative. Weinstein added that the U.S. Preventive Services Task Force did not endorse screening for hearing loss or for cognitive decline, partly because studies have not been conducted demonstrating that interventions will have a beneficial effect relative to screening outcomes. It is also important, Weinstein added, that the efficacy of hearing aids in improving hearing quality of care and life be measured, because people with hearing aids have other health-related issues as well.
Margaret Wallhagen, University of California, San Francisco, who spoke later in the workshop, raised a concern about the ethics of randomized controlled trials if someone is not provided with a useful intervention. Observational studies are able to produce solid findings, as with cigarette smoking and cancer. Causative information is important, and randomized controlled trials are usually the gold standard, but creative research designs also can yield useful information.
Ferrucci emphasized the importance of being able to tell who will do well and who will not do well with a hearing aid. Also, the correlation of hearing loss with medical conditions provides an opening to involve primary care physicians in hearing issues. Jette added that community participation is another important factor. Important social roles can be severely compromised by hearing loss, and these societal roles deserve much more investigation.
Firman pointed out that trials should look not just at the efficacy of hearing aids but also at other forms of hearing rehabilitation, such as speech reading.
Diversity and Accessibility Issues
On a more provocative note, Firman said that much of the research on hearing and healthy aging can be seen as ageist. It starts with the assumption that the most important issue is enabling people to maintain physical or psychosocial function, but the more important questions involve their ability to work. “We know that one-third of older people have to work. They don’t have financial resources to do otherwise.” Similarly, to what extent are older people able to volunteer or participate in informal family care? he asked. “If we start with the view that this is just about nonfunctioning people who are not expected to contribute to society, that is an ageist point of view. We have to turn this around and say, ‘We have this tremendous resource of 78 million people as the baby boomers are grow-
ing older. The most important imperative is to keep them working and contributing.’”
Pichora-Fuller observed that hearing problems are very diverse, which means that no one solution is sufficient. This diversity creates problems for clinicians, who have to decide how best to help their patients. For example, perhaps the many people with hearing loss who do not use hearing aids need different kinds of solutions. Diversity also complicates the question of when interventions should be undertaken. In an analogy with hypertension, clinicians do not want to wait for someone to have a heart attack before they start educating that person about changing lifestyles and taking other soft interventions. This question, said Albert, is the kind of problem that randomized controlled trials can address.
Pichora-Fuller also recounted some advice she once received from someone in a wheelchair. He recommended not talking about hearing loss because that made the problem too narrow of an issue to appeal to the population as a whole. A far better approach, he said, is to talk about communication accessibility in the spirit of universal design (see Chapter 6) to ensure that everyone has an environment that is conducive to communicating.